Computer devices and other integrated circuit devices may need to transmit messages or to receive messages from other devices. In some cases, the message transmission may occur between two interconnected devices or between a large number of devices forming a network. In such a network, one or more of the devices may be in the form of computer apparatus and other devices may comprise a variety of peripheral equipment. Such networks may include routing switches to permit a wide range of interconnections throughout the network. The transmission of data between such connected devices can be accomplished by using parallel data buses or serial communication wires. Complications arise in controlling buses in such network connections and furthermore the speed of operation is particularly limited where two or more devices are connected in the network.
It is an object of the present invention to provide a simple high speed interface between such communicating devices. It is an object to permit high speed operation without loss of data and to permit messages of variable length to be transmitted in multiple packet form. This is advantageous in permitting any interface to handle packets of different messages in succession before completing transmission of all packets of any one message.
It is an object of the invention to provide an improved bidirectional communication interface using four unidirectional signal wires.